Blue anthraquinone dye and process of making same.



UNTTIED STATES PATENT Orrrcn.

ROBERT E. SCHMIDT, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBEN- FABRIKENOF ELBERFELD (10., OF NEW YORK, N. Y.

BLUE ANTHRAQUINONE DYE AND PROCESS OF IVIAKING SAME.

SEEGIJEZ 'JATIQN forming part of Letters Patent No. 675,572, dated June4, 1 901. Application filed December 29, 1900. Serial No. 41,476.(Specimen) To (M7 whom it nmg concern.-

Be it known that I, ROBERT E. SCHMIDT, doctor of philosophy, chemist,(assignor to the FARBENFABRIKEN on ELBERFELD COM- PANY, of New York,)residing at Elberfeld, Germany, have invented a new and usefulImprovement in Blue Anthraquinone Dyes and Processes of Making Same; andI hereby declare the following to be a clear and exact description of myinvention.

My invention relates to the manufacture of new blue dyestuft' snlfonicacids of the anthracene series by causing sulfonating agents to act onanthraquinone derivatives having the following general formula: I

NIHL W t W I W w I I I I I v with primary aromatic amins-such as anilin,paratoluidin, Xylidin, or the like-in the presence of condensing agents,such as boric acid or the like.

In this process the hydroxy group is replaced by an alphylarnido radicaland the condensation products of the above-given general formula areproduced. The said bodies can also be obtained by treating, forinstance, alpha -alpha -nitroamidoanthraquinone with the above-mentionedaromatic amins. By this operation the nitro group is replaced by analphylamido radical. The new dyestuff sulfonic acids thus obtained are,in a dryst-ate, dark powders which are soluble in water and in ammoniawith a blue color. They dye u11- inordantcd and chrome-mordanted woolfast blue shades. In order to produce the saidamidoalphylamidoanthraquinones, I can proceed as follows, the partsbeing by Weight: Ten parts of alpha -alpha,-amidooxyanthraquinone aremixed with one hundred parts of paratoluidin and live parts ofcrystallized boric acid. This resulting mixture is heated to about from14:0 to 160 centigrade until the color of the melt turns from red toblue. After the reaction mass has been allowed to cool it is mixed withmethylic alcohol, by means of which operation the condensation productseparates after some time in the shape of dark-blue crystals.Subsequently it is filtered off and dried. The resulting body is readilysoluble in chloroform, pyridin, and anilin with an intense blue color.It is soluble With difficulty in methyl and ethyl alcohol. In order totransform this condensation product into the new dyestuff sulfonic acid,ten parts of the finely-pulverized compound are stirred into from onehundred to two hundred parts of sulfuric monohydrate. The re sultingsolution is then heated to about from 60 to 100 centigrade until a testportion is clearly dissolved by a large quantity of hot Water.Subsequently the reaction mass is poured into about from one thousand totwo thousand parts of Water, by means of which operation the newdyestuff sulfonic acid, Which is very difficultly soluble in diluteacids, is precipitated. It is filtered off, washed with a solution ofcommon salt, and dried.

WVhen dry and pulverized, the new coloring-matter is a dark-blue powder,which is rather difficultly soluble in cold and more soluble in hotwater with a blue color. It is easily soluble in ammonia, in ethylalcohol, (of ninety per cent.,) and in acetic acid, (of fiftyper cent.)with a blue color. By the addition of hydrochloric acid to its Waterysolution the color of the latter turns redder, and by the addition ofammonia to this acid solution the original blue color is again produced.By concentrated sulfuric acid (of 66 Baum) it is dissolved, yielding aviolet solution, the color of which changes into red on eral formula:

NHR

in which formula R means an alphyl radical, with sulfonating agents andthen isolating the resulting dyestuif sulfonic acids from the reactionmixture, substantially as hereinbefore described.

2. The process for producing a new anthraquinone dyestuff, which processconsists in first treating alpha -amido-alpha-para-tolylamidoanthraquinone having the formula:

Ni O,H,-CH with sulfonating agents, and then isolating the resultingdyestuff sulfonic acid'from the reaction mixture, substantially ashereinbefore described.

3. The herein-described new dyestuff sulfonio acids, obtainable bysulfonating alpha,- amido alpha alphylamidoanthraquinones, whichdyestuffs, when dry and pulverized, are dark powders soluble in waterand in ammonia with a blue color, dyeing unmordanted andchrome-mordanted wool fast-blue shades, substantially as hereinbeforedescribed.

4. The herein-described new dyestuff sulfonic acid, obtainable bysulfonating alpha,- amid0-alpha paratolylamidoanthraquinone, whichdyestuff is, when dry and pulverized, a dark blue powder being ratherdifficultly soluble in cold and more soluble in hot water with a bluecolor, being easily soluble in ammonia, in ethyl alcohol (of ninety percent.) and in acetic acid (of fifty per cent.) with a blue color, thecolor of its watery solution turning redder by the addition ofhydrochloric acid and the original blue color being produced again byadding ammonia to the acid solution; being dissolved by concentratedsulfuric acid (of 66 Baum) yielding a violet solution the color of whichchanges into red on the addition of a small quantity of ice, while onadding a larger quantity of ice the dyestuff sulfonic acid separates inthe shape of a dark precipitate; dyeing unmordanted and chrome mordantedwool blue shades fast to light and to alkalies, substantially ashereinbefore described.

In testimony whereof I have signed my name in the presence of twosubscribing wit-' nesses.

ROBERT E. SCHMIDT.

Witnesses:

OTTO KONIG, J. A.- RITTERSHAUS.

